Best answer

In my testing deleting a response in an active survey with quotas applied frees up a spot in your quota.

So let’s say you have a quota of 5 and have collected two responses, your quota would read as being 2/5 full. If you deleted one response, your quota would read as 1/5 full and would allow four additional responses.

I would maybe suggest testing this out on a random test survey of yours to confirm.